The long-term effect of non-native earthworm species on forest soil carbon storage is not clear. While initial invasion into earthworm-free soils stimulates carbon losses, there is evidence that carbon stabilization in soil aggregates is enhanced. Fourteen managed forest sites throughout Vermont were sampled to identify and enumerate earthworms, and determine soil aggregate distribution and physically protected carbon. Most of these sites were northern hardwoods reforested in the mid-20th century after agricultural land use. Soil at six 50 x 50 cm subplots at each site was sampled to a depth of 20 cm below the Oe horizon and the mineral soil fractionated into free microaggregates (<250 mu m), small macroaggregates (250-2000 mu m), and large macroaggregates (>2000 mu m). Microaggregates were then isolated from the macroaggregates and organic carbon determined. Mean earthworm numbers below the Oe horizon at each site ranged from 0 to 313 individuals m(- 2) and ten different species were identified, representing all earthworm ecotypes. Four sites had no earthworms in the soil layer sampled, three sites had earthworms in every subplot with up to six different species, and seven sites had subplots both with and without earthworms. When subplots were grouped by number of species present, there was a trend towards a greater fraction of the mineral soil in macroaggregates containing greater protected carbon, and a lower fraction of free microaggregates. A paired t-test of subplots from the seven sites with variable earthworm presence showed significant differences in the same trends and there was significantly greater mineral soil total carbon and protected carbon in the subplots with earthworms. These results are consistent with recent research into earthworm effects on soil carbon stabilization. While initial invasion likely resulted in a negative carbon balance, our findings suggest that earthworms can enhance transfer of carbon into physically protected pools in these forest soils.

This research tested whether mycorrhizae can rejuvenate the water quality and pollinator functions of degraded riparian forested buffers (RFBs) in agricultural landscapes while facilitating indigenous Abenaki access to ancestral lands. Two plots within a degraded RFB were restored with a multi-functional plant community, one plot inoculated with commercial mycorrhizae and the other without. A control plot remained in a degraded state dominated by the invasive shrub Rhamnus cathartica. The restoration palette of 32 plants included 28 species useful to the Abenaki, representing opportunities for phosphorus removal through harvesting. Monitoring data from 2020 to 2023 indicated consistently greater plant diversity in the restored plots, with 58 newcomers appearing. Although the total phosphorus (P) decreased over time in all the treatments, the greatest decrease was in the uninoculated plot, likely due to pathogenicity from the commercial inoculant or the spatial variability of soil and light. The biomass P of five plant species differed among the species but not among the treatment plots. Nonetheless, Abenaki harvesting removed P and can be an effective form of phytoremediation, phytoextraction. However, this research revealed trade-offs between P mitigation, indigenous use, and pollinator functions of the RFB. Fostering higher biodiversity, Indigenous land access, and P mitigation are important solution-oriented aims to balance when restoring degraded RFBs.

Apolocystis bosanqueti n. sp., a parasite of an important invasive earthworm in North America, Amynthas agrestis, is described from a site in northern Vermont. The earthworm host follows an annual life cycle in Vermont, so the entire life cycle of the parasite can be observed in 7 mo. In spring, the parasites were first seen in juvenile worms as paired gamonts (suggesting precocious association). These paired gamonts mature into gametocytes that form an opaque structure, with a thick gelatinous envelope (epicyst), that becomes full of zygotes. The resulting gametocyst becomes packed with ∼105 fusiform oocysts. The mature orbicular gametocysts are large (∼1 mm in diameter) and visible to the naked eye through the body wall of the host's anterior segments. The new species most resembles Apolocystis herculea described from many lumbricid earthworm species in Europe but differs from that parasite because Ap. herculea infects the intestinal wall in the posterior of the host rather than the anterior segments. A survey of 9 other earthworm species sympatric with Am. agrestis revealed that only Amynthas tokioensis, also an invasive species, was infected with Ap. bosanqueti, albeit much less commonly. Diagnosis for the family Monocystidae is problematic because cardinal characters are lacking, and the commonly cited character, a trophozoite with no anterior differentiation, is violated in most genera placed in the family. For the first time, a molecular phylogeny is presented that includes 3 genera of monocystids with diverse cell morphology (including the new species) and supports the monophyly of the family. The only morphological character that may be used to diagnose the Monocystidae is the morphology of oocysts, which are fusiform with extended terminal tips. A comparison of oocysts from 7 parasites recovered from local earthworms, including from 3 monocystid species in the phylogeny, confirms the utility of this diagnostic trait. The 2 hosts of the new species were most likely introduced from Japan, so the range of Apolocystis likely extends into East Asia.

Agricultural pollution, especially phosphorus (P) can cause eutrophication of freshwater quality. Riparian buffers are best management practices (BMPs) which intercept agricultural pollution. However, they are frequently degraded by reduced biodiversity. P mitigation in riparian buffers can be enhanced through mycorrhizal inoculation and cyclical coppicing. We report on a myco‐phytoremediation project that investigates mycorrhizae's effect on vegetation's ability to lower legacy soil P, soil water P, and increase woody biomass P uptake. It also aimed to restore pollinator habitat through planting a diverse, native plant palette (32 species), blooming from February to November. Planting and offering culturally relevant plant materials to the Abenaki contributes to their land rematriation process. The study was located on unceded Abenaki territory at Shelburne Farms, within 300 m of Lake Pitawbagw (Lake Champlain) which is impacted increasingly by P pollution from colonial and conventional agricultural practices. Along a drainage way three treatment plots were installed: buckthorn vegetation (OIV) left in place as the control, and two restored diverse multi‐synusium plant communities, consisting of either uninoculated (RV) or inoculated with 19 mycorrhizal species (RVM). After 2 years, soil water soluble reactive P extracted from lysimeter samples was not affected by treatment but varied over time. However, water extractable SRP (WEP‐SRP) and TP (WEP‐TP) followed this trend RV > OIV > RVM which was inversely and linearly related to mycorrhizal density. Plants are best harvested in late summer when P concentrations are highest. Restoration science can flourish through reciprocally partnering with Original Peoples who hold expertise in ecological reconciliation.

The introduction of invasive earthworms initiates physical and chemical alterations in previously earthworm-free forest soils, which triggers an ecological cascade. The most apparent step is the shift in the herbaceous plant community composition. However, some species, such as Arisaema triphyllum (jack-in-the-pulpit), persist where earthworms are present. It has been hypothesized that A. triphyllum produces insoluble oxalate, an herbivory deterrent, in the presence of earthworms. This study aimed to distinguish between the effects of earthworm-induced changes in soils and the physical presence of earthworms on oxalate production. As such, a two-way factorial greenhouse trial was conducted using uninvaded soils to test this hypothesis for two invasive earthworm species (Amynthas agrestis and Lumbricus rubellus). The sequential extraction of oxalates in A. triphyllum corms was performed with absolute ethanol, deionized water, acetic acid and HCl, representing fractions of decreasing solubility. Earthworm presence increased water-soluble (p = 0.002) and total oxalate (p = 0.022) significantly, but only marginally significantly for HCl-soluble oxalate (p = 0.065). The corms of plants grown in soils previously exposed to the two species did not differ in oxalate production when earthworms were not present. However, the data suggest that earthworms affect corm oxalate concentrations and that the sequence of invasion matters for oxalate production by A. triphyllum.

Composting is a common waste management strategy for recycling nutrients from organic household or agricultural wastes. However, thermophilic (e.g. windrow) composting and vermicomposting (using earthworms) produce different nutrient and enzyme profiles. Vermicompost is purported to have greater fertility benefits, but is also more expensive than thermophilic compost. The objective of this study was to examine a novel approach to designing organic fertility amendments by blending mature vermicompost and thermophilic compost. To examine the effect of blending, vermicompost was admixed to thermophilic compost at 20, 50 and 70 % by mass, with and without the addition of coir (cocopeat). Electric conductivity, water-extractable, immediately available N, P and K were measured. Vermicompost and coir synergistically affected the availability of these nutrients. Synergistic effects were between 15 and 40 % for total inorganic N in blends with coir. Without coir, synergism occurred only at vermicompost additions ≥50 %. Synergism for available P and K was present in all blends and ranged from 10% to 35%. Electrical conductivity measurements suggest that blending affected compost within three days of starting the incubation. The activity of five of seven measured enzymes were linearly and positively related to the fraction of vermicompost in the blend. Blending mature composts with differing properties may be another tool, in addition to adjusting feedstock and process parameters, to affect positively the fertility properties of composts.

Societal Impact Statement Worldwide, farmers struggle to find the most efficacious practices which balance crop fertility needs and water quality protection. Through a greenhouse experiment, we investigated how soil status (high vs. low phosphorus [P] concentration), mycorrhizae (inoculated vs. not), and plant species (dogwood vs. willow) affected P plant uptake and leaching. We found mycorrhizae did not affect uptake or leaching, more P was leached from high than low P soil, dogwood uptook yet leached more P, and above ground biomass at the end of summer contained more P than roots. This study provides insights to be considered by researchers and practitioners who implement best management practices for water quality. Summary This research examined the effects of mycorrhizal inoculation in high and low phosphorus saturation soils on phosphorus uptake by Cornus sericea and Salix niger. The aim was to identify practices that improved water quality functions of riparian buffers to protect surface waters impacted by eutrophication. A mesocosm experiment arranged as a random block design was conducted with mycorrhizal presence, soil phosphorus saturation status, and plant species as factors. Leachate, plant uptake, and soil phosphorus were measured to assess the effects. Greater leachate and uptake of phosphorus were detected for C. sericea than for S. niger. Mycorrhizae had no effects on leaching nor on uptake of phosphorus in this experiment. High phosphorus saturated soils had greater leaching and uptake than the low phosphorus soils. Above ground biomass contained more phosphorus than below ground biomass in both species at time of harvest. Estimations of phosphorus removal through coppicing suggest a very slow removal rate in biodiverse multi‐functional riparian buffers. Our results suggest that cyclical coppicing can be an improvement to Best Management Practices. Diverse riparian buffers are limited in the amount of phosphorus that they can store and mitigate, even with coppicing. The emphasis therefore should be on agricultural best management practices that reduce phosphorus export from upland fields. Further studies in phosphorus accumulating plant species with appropriate mycorrhizal symbionts are needed.

The invasive Asian earthworms, Amynthas tokioensis and A. agrestis, have been successful in entering North American forests in recent decades, with significant damage to both soils and above-ground environments. This success could be driven in part by a polyploid genetic system and parthenogenetic reproduction, often suggested as benefits for invasive species. Therefore, we assessed the genetic population structure, genetic diversity, and reproductive system of both species using morphological traits and panels of microsatellite markers. A total of 216 A. tokioensis and 196 A. agrestis from six sites in Vermont USA were analyzed. Although all worms were morphologically hermaphroditic, all the A. agrestis lacked the male pore (the structure allowing pass of sperm between individuals), and only 19% of the A. tokioensis possessed the male pore. All A. tokioensis earthworms were triploid (scored for three alleles for at least 1 locus, and usually several), and A. agrestis was a mix of triploid and diploid individuals. Notable was the high proportion (80%) of A. agrestis earthworms that were diploid at one site. There was clearly clonal reproduction, with identical seven- locus genotypes observed for earthworms from each site, with as many as 45 individuals with the identical genotype at one site. However, the earthworms were also genetically diverse, with 14 genotypes observed for A. tokioensis and 54 for A. agrestis, and with many singleton genotypes (a single individual). Most genotypes (71% for A. tokioensis and 92% for A. agrestis) were found at a single site. The greatest number of genotypes was found at a commercial nursery where fully 23/26 A. agrestis earthworms were singleton genotypes. As expected for the pattern of private clone alleles at sites, several measures of geographic genetic differentiation were positive, and as expected for triploid systems, an AMOVA analysis showed high within-individual genetic diversity. The paradox of clear clonal reproduction, but with a great number of genotypes for each species, and the mix of triploid and diploid individuals could be explained if the worms have been sexually reproductive, with the switch to the uniparental system only recently (or even if sexual reproduction is episodic). Last, a large number of microsatellite loci were recovered for each species and there sequence and suggested PCR primers are provided for free use by other researchers.

During this 6th Great Extinction, freshwater quality is imperiled by upland terrestrial practices. Phosphorus, a macronutrient critical for life, can be a concerning contaminant when excessively present in waterways due to its stimulation of algal and cyanobacterial blooms, with consequences for ecosystem functioning, water use, and human and animal health. Landscape patterns from residential, industrial and agricultural practices release phosphorus at alarming rates and concentrations threaten watershed communities. In an effort to reconcile the anthropogenic effects of phosphorus pollution, several strategies are available to land managers. These include source reduction, contamination event prevention and interception. A total of 80% of terrestrial plants host mycorrhizae which facilitate increased phosphorus uptake and thus removal from soil and water. This symbiotic relationship between fungi and plants facilitates a several-fold increase in phosphorus uptake. It is surprising how little this relationship has been encouraged to mitigate phosphorus for water quality improvement. This paper explores how facilitating this symbiosis in different landscape and land-use contexts can help reduce the application of fertility amendments, prevent non-point source leaching and erosion, and intercept remineralized phosphorus before it enters surface water ecosystems. This literature survey offers promising insights into how mycorrhizae can aid ecological restoration to reconcile humans' damage to Earth's freshwater. We also identify areas where research is needed.

Forest soils store a globally important pool of carbon (C) and reforestation has the potential to increase this pool. Past land use, tree species composition, and current management are known to affect carbon storage rates and amounts. Another important factor, especially in the vertical distribution of soil C, is the presence or absence of earthworms. We investigated these interactions in eighteen managed forest sites in Vermont that have varied land use history (cultivation, pasture, woodlot, continuous woodland) and a range of time since reforestation from 60 to 100+ years. Soils were sampled to about 1 m, or shallower if bedrock was reached, and both C and exchangeable cation pools quantified. Earthworms were enumerated to a depth of 20 cm and identified by species. Basal area by tree species was also measured and aboveground C calculated. Detailed land use history was documented using archival sources. Forest type was primarily northern hardwood, with a few lowland spruce-fir sites included. Eleven different species of earthworms were found, representing all ecotypes, and numbers ranged from 0 (at 8 of the 18 sites) to 319 individuals/m2. Carbon pools in the forest floor (1.5?30.1 Mg/ha) were greater with higher site elevation (range of 154?651 masl) and also greater with lower numbers of earthworms. Besides elevation, the best predictor of earthworm presence or absence, and overall numbers, was the soil exchangeable calcium (Ca) pool in the Oa and A horizons (range of 9.4?1288 cmolc/m2). Because soil exchangeable Ca and aluminum (Al) pools were inversely related, higher exchangeable Al was associated with lower earthworm numbers. In the mineral soil, the C pool (82.1?210.8 Mg/ha) was best explained by the thickness of the B horizons with the exchangeable Al pool as a positive, secondary factor. The thickness of the A horizon (0?16.3 cm), and its contribution to the entire profile C pool (0?54.7 Mg/ha), decreased relative to past land use in the order: cultivated < pasture < woodlot. No earthworm metric was strongly related to the C pool in either the mineral soil or the full soil profile. Dramatic differences in the vertical distribution of carbon were related to past land use and earthworm presence, which in turn was negatively correlated with elevation and the presence of conifers. While it is clear that earthworms and prior land-use have a long-lasting effect on the forest floor C pool, it is less clear whether or not there is an effect on full profile C sequestration over time.

BACKGROUND:Invasive species cause enormous costs of over $120 billion to the U.S. economy. Among biological invasions, the invasion by pheretimoid earthworms has gone relatively unnoticed and their invasion imposes yet unknown damage on USA agriculture and horticulture. The main dispersal is with horticultural goods such as plant material and composts. Pheretimoids affect commercially important hardwood forest. With no chemical agents currently certified for earthworm control nor any best horticultural practices, slowing the invasion is difficult.METHODS:In this study we measured the efficacy of a commercial entomopathogenic fungal isolate of B. bassiana (BotaniGard®) to kill pheretimoid earthworms under greenhouse conditions. Four treatments of B. bassiana were applied: The commercial product as per label, re-cultured commercial B. bassiana, 15 g and 25 g millet grains mycotized with recultured product. In all, three bioassays were conducted in 2 consecutive years with two batches of BotaniGard®.RESULTS:With fresh batches, all B. bassiana treatments with re-cultured product resulted in greater than 70% mortality within 4 weeks. Mortality was less than 60% when BotaniGard® was used as prescribed by the label. When using 1-year old spores (refrigerated at 4 °C), mortality rates for B. bassiana treatments were less than 20% and not significantly different from the controls. However, B. bassiana still affected the earthworms by slowing their development from juvenile to adult stage.CONCLUSION:B. bassiana was effective against pheretimoid earthworms. Overall, mycotized millet grains did not significantly increase mortality over the re-cultured, directly applied B. bassiana spores. More experimentation is needed to find the mode of action of the re-cultured B. bassiana before investigating ways to improve the efficacy of B. bassiana when applied as prescribed on the label.

Invasive earthworms can increase both pH and the nitrate concentrations in northern hardwood forests while nitrification is an acidification source. To obtain the nitrogen deposition impact, the soil pH, Ca, greenhouse gas emissions, and inorganic nitrogen forms have been compared for NH4+-N added and not added spodosol soils at aggregate scale inhabited by Amynthas agrestis (A) (ivasive/non-calciferous), Lumbricus rubellus (R) (non-invasive/calciferous), or no earthworm (C). Soils were classified into the three earthworm treatments by Naive Bayes classification using all gas emissions, Ca, and pH (misclassification rate of 9.3%). There were significant differences among the earthworm treatments in pH, Ca, N2O, and CO2 emissions. pH varied among earthworm treatments (A < C < R) and reduced over time for all three treatments. Water-soluble Ca and N2O emissions were greater in R than in A soils. Both earthworm treatments had greater NO3-N concentrations than the control. Stepwise regression identified Ca (4 out of 5 incubations, positive effect, explaining 11% to 26% of pH variance) and CO2 evolution (4 out of 5 incubations, negative effect 4% to 47% of pH variance) as the two most consistent predictors of pH. We consider the earthworm invasion may be an alternative buffering agent for the nitrogen deposition for forests.

Computer simulations are widely used to explore options and quantify outcomes in agriculture. For example, mathematical models have been used to estimate how much of the nitrogen (N) and phosphorus (P) delivered to the Gulf of Mexico comes from agricultural sources (Alexander et al. 2008); to calculate changes in grain yields as management practices are varied (Chen et al. 2014); and to investigate the effects of different precipitation regimes on soil erosion (Nearing et al. 2005). Physical models can be linked with economic and behavioral data to calculate potential costs, such as those of treating or replacing household well water contaminated by nitrates (NO3) as grassland is converted to row crops (Keeler and Polasky 2014). Models can also estimate risk, such as that of crop failure in various climate change scenarios (Challinor et al. 2010). A wide variety of scales and systems can be simulated, from assessing farmers’ behavioral responses to climate change-related policies on a patchwork of single farms (Berger and Troost 2014), to predicting global losses of staple crops due to pest damage in a warmer world (Deutsch et al. 2018).

The northeast United States has experienced higher temperatures, more annual precipitation, and more frequent heavy rain events in recent decades. These trends appear likely to continue, and they may depress crop yields and exacerbate environmental problems associated with the region’s dairy farms. To investigate these possibilities, we used the Agricultural Policy/Environmental eXtender (APEX) model to simulate runoff, erosion, nutrient losses, and crop yields on two Vermont farms in a small set of possible future climates. Raising temperatures by 2°C, combined with increasing total precipitation or changing the seasonality of precipitation, had relatively modest effects on any outcome (less than 10% change in median values). However, a combination of higher temperatures and more intense precipitation led to increased runoff volumes and larger soil and nutrient losses. Median values of runoff, sediment, and nutrient losses increased by 2% to 15% at one site and by 36% to 58% at the other (although the changes at the latter site were relative to very low baseline values), while the 95th percentile rose by 6% to 19% and 53% to 65%. This suggests that management practices adapted to reducing runoff etc. in extreme precipitation events will be increasingly valuable in the coming years. Corn (Zea mays L.) silage yields changed by less than 10% in all simulations, and in some cases increased slightly. However, modeling that includes many additional factors that can reduce yields (such as new pests, or delays to farm operations in wet conditions) is needed for a more complete understanding of how climate change may affect the viability of forage production on dairy farms in this region.

The invasion of jumping worms, a small group of pheretimoid earthworm species from Asia, has increasingly become an ecological, environmental and conservation issue in forest ecosystems and urban-suburban landscapes around the world. Their presence is often noticed due to their high abundance, distinctive "jumping" behavior, and prominent granular casts on the soil surface. Although they are known to affect soil carbon dynamics and nutrient availability, no single paper has summarized their profound impacts on soil biodiversity, plant community, and animals of all trophic groups that rely on soil and the leaf litter layer for habitat, food, and shelter. In this study, we summarize the biology, invasion, and ecological impacts of invasive jumping worms across North America. We highlight potential impacts of this second wave of earthworm invasion, contrast them with the preceding European earthworm invasion in temperate forests in North America, and identify annual life cycle, reproductive and cocoon survival strategies, casting behavior and co-invasion dynamics as the key factors that contribute to their successful invasion and distinct ecological impacts. We then suggest potential management and control strategies for practitioners and policy makers, underscore the importance of coordinated community science projects in tracking the spread, and identify knowledge gaps that need to be addressed to understand and control the invasion.

Identification of taxa that are morphologically very similar is a standing problem in ecology and is particularly important for invasive species that may differ in their dispersal rates and environmental and economic costs. Three similar pheretimoid earthworms (genera of Amynthas, Metaphire) are important invasive species in North American forests. They often lack the diagnostic morphological characters and their hatchlings, juveniles, and cocoons are impossible to identify to species. We present a multiplex PCR protocol that accurately scores the three species and is inexpensive compared to other molecular methods. Multiplex PCR identification was as accurate as mitochondrial COI barcoding and better than morphological scoring. The method uses unique PCR fragments of different lengths for each species from the COI gene. The multiplex PCR correctly identified embryos within cocoons, juveniles, and adults of Amynthas agrestis, Amynthas tokioensis and Metaphire hilgendorfi, with 100% accuracy. Comparisons of COI sequences (GenBank) with other populations of the same species (including specimens from their native range in Japan), and many other species of earthworms showed the primers always amplify only the three target species. The multiplex PCR method is rapid and costs a fraction of standard COI barcoding. Also, tiny scratches of cells from living specimens can be entered directly into the PCR for easy identification, reducing costs even further by avoiding DNA extraction, and allows the earthworms to be conserved for ecological experiments. To show the utility of the method we present the hatching phenology of the three species which could not be done by morphology. The three species begin hatching at the same time with A. tokioensis producing the most abundant juveniles early in the season. The method facilitates studies on biogeography, phenology, life histories, and resource partitioning among the three co-occurring earthworm species.

Soil fauna includes earthworms, collembolans, mites, nematodes, and protozoa. These are eukaryotic, heterotrophic, motile organisms that require oxygen for metabolism. Their physical range, habitats, and food resources are constrained by their respective sizes and the availability of pores of appropriate size within the soil. This chapter describes both invertebrate animals that live in the soil and their habitat and additionally examines their activities in the context of the soil foodweb. We focus on the role of soil animals in controlling microbial pathogens, mineralizing nutrients, changing microbial community composition, and enhancing primary production. Like aboveground fauna, the physical structure of the ecosystem places constraints on the activities of the soil fauna, especially in relation to the microflora. As a result of their feeding, burrowing, and movement, the soil fauna also engineer the habitat for the soil microflora, transport beneficial and pathogenic microorganisms, and affect the production of detrital resources from plants.